CN103412218A - Detection circuit for working condition of ceramic heater strip and corresponding method - Google Patents

Abstract

The invention discloses a ceramic heating wire working condition detection circuit and a corresponding method, belonging to the field of ceramic heating wire working state detection. Among them, the ceramic heating wire working condition detection circuit includes: a control module, an electronic switch module, a heating wire driving module, a heating wire protection module, a detection processing module, and a voltage conversion module. The working condition detection circuit of the ceramic heating wire provided by the present invention cooperates with the detection method described in the present invention, utilizes the resistance characteristic of the ceramic heating wire itself, overcomes the problem of large current of the detection circuit, and realizes the detection purpose. The working state of the ceramic heating wire is judged by sending out detection signals and control signals by the control module at different times. The invention makes full use of the characteristics of the heating wire itself to form a detection circuit, the circuit is simple and reliable, and the detection accuracy is improved.

Description

A ceramic heating wire working condition detection circuit and corresponding method

technical field

The invention belongs to the technical field of ceramic heating wire detection, and in particular relates to a ceramic heating wire working condition detection circuit and a working condition detection method thereof.

Background technique

In the vehicle liquid heater, the heating wire is generally made of metal resistance wire, but due to its own characteristics, the heating temperature of the heating wire is usually not high enough, and it is easy to be corroded. Nowadays, ceramic heating wires with rapid temperature rise, high surface temperature and corrosion resistance are used in some vehicle liquid heaters. However, in the working process of the ceramic heating wire, (1) the ceramic heating wire is used in the vehicle liquid heater, and the resistance value of the heating wire itself is small, so the detection circuit bears a large current. (2) Some unexpected situations may occur during use, such as ceramic heating wire open circuit, short circuit and a series of conditions that make the system unable to work normally when the system is working. The occurrence of these faults will cause the heater to stop working directly, and the serious one will cause the equipment to malfunction. permanent damage, and may cause some major safety accidents. Therefore, overcoming the detection difficulties and inventing a detection circuit for accurately and real-time judging the working condition of the ceramic heating wire is very important for ensuring the safety of the equipment.

Contents of the invention

The purpose of the embodiments of the present invention is to address the above existing problems, provide a ceramic heating wire industrial and mining detection circuit and a method for detecting the working conditions of the heating wire, and solve the problem of accurate detection of various working conditions of the ceramic heating wire.

The technical solution of the embodiment of the present invention is achieved as follows: the purpose of the embodiment of the present invention is to provide a detection circuit of a DC motor, including: an electronic switch module, the input end of the electronic switch module is connected to the control module Control the pulse signal output terminal, the output terminal of the electronic switch module is connected to the signal input terminal of the heating wire driving module; the heating wire driving module, the power input terminal of the heating wire driving module is connected to the power supply of the detection circuit Positive electrode, the output end of the heating wire driving module circuit power supply is connected to the heating wire protection module; the heating wire protection module, the input end of the heating wire protection module is connected to the feedback signal input end A of the detection processing module; detection processing module, the detection signal input terminal B of the detection processing module is connected to the detection signal output terminal of the control module, and the detection signal output terminal C of the detection processing module is connected to the feedback voltage input terminal of the voltage conversion module; A conversion module, the output end of the voltage conversion module is connected to the feedback signal input end of the control module.

The electronic switch module circuit is composed of triode _Q1 , capacitor _C4 , resistors _R5 and _R6 ; resistor _R5 is connected to the control signal output terminal of the control module and the base of triode _Q1 to realize the limit of the base of triode _Q1 . The role of current flow; capacitor _C4 is connected between the base of the triode _Q1 and the resistor _R5 ; resistor _R6 is connected between the positive pole of the detection circuit power supply and the collector of the triode _Q1 to realize the limit of the collector flow protection.

The heating wire drive module circuit includes: automatic protection power MOSFET power driver Q ₂ , resistor R ₇ , diode D ₂ and capacitor C ₁ ; resistor R ₇ is connected to the signal output terminal of the electronic switch module circuit and the power MOSFET power driver Between the gates of Q ₂ , signal integrity problems such as signal overshoot are weakened or eliminated; Capacitor C ₁ is connected between the drain of the power MOSFET power driver Q ₂ and the power ground layer of the detection circuit; the power MOSFET The drain of the power driver _Q2 is connected to the positive pole of the power supply of the detection circuit, and the source of the power MOSFET power driver _Q2 is connected to the P pole of the diode _D2 ; the detection circuit utilizes the unidirectional conduction characteristic of the diode _D2 to prevent detection When the detected current is poured back into the source of the power MOSFET power driver _Q2 , it plays a role in protecting the safety of the device.

The heating wire protection module circuit includes: ceramic heating wire R _GP , capacitor C ₃ , fuse F ₁ and transient suppressor D ₁ ; capacitor C ₃ and diode D ₁ are connected between the N pole of the diode D ₂ and the detection circuit between the power ground planes; the fuse _F1 is connected between the ceramic heating wire R _GP and the power ground plane of the detection circuit, and plays an overcurrent protection role for the ceramic heating wire R _GP .

The detection processing module circuit includes: resistance R ₁ , resistance R _{2 ,} resistance R ₃ , resistance R ₄ , capacitor C ₂ and diode D ₃ ; resistance R ₁ is connected to the feedback signal input terminal A of the detection processing module circuit and the The other end of the resistor _R2 is directly connected to the N pole of the diode _D3 ; _the P pole of the diode _D3 is connected to the detection signal input terminal B of the detection processing module; the diode _D3 is used To prevent the driving current of the ceramic heating wire from pouring back into the control module circuit, causing the control module to malfunction; the other end of the resistor _R4 is connected to the power ground of the detection circuit.

The voltage conversion module circuit includes: analog/digital converter _U5 ; the input end of analog/digital converter _U5 is connected at the detection signal output end C of the detection processing module, and the output end of analog/digital converter _U5 is connected Feedback signal input to the control module.

The purpose of the embodiments of the present invention is also to provide a method for detecting the working condition of the ceramic heating wire. The method for detecting the working condition of the ceramic heating wire cooperates with the detection circuit of the ceramic heating wire to detect various working conditions of the heating wire. The detection method of ceramic heating wire includes the following steps:

S1: Before starting to detect the state of various working conditions of the ceramic heating wire, first record the current control command of the control module;

S2: Determine whether the command of the control module is to turn on the ceramic heating wire;

S3: If yes, the feedback signal input terminal of the control module directly reads the data at the output terminal of the voltage conversion module;

S4: If not, the detection signal output port of the control module sends a detection signal, and the feedback signal input port reads the data at the output end of the voltage conversion module;

S5: Turn off the heating wire detection signal at the detection signal output end of the control module in the ceramic heating wire detection circuit;

S6: According to the voltage data output by the voltage conversion module received by the control module, directly judge the various working conditions of the ceramic heating wire;

S7: According to the determined working state of the ceramic heating wire, the control module adopts corresponding processing procedures to ensure the normal operation and safety of the system.

Description of drawings

Fig. 1 is a schematic diagram of the module structure of a ceramic heating wire industrial and mining detection circuit provided by an embodiment of the present invention;

Fig. 2 is a schematic circuit diagram of a ceramic heating wire industrial and mining detection circuit provided by an embodiment of the present invention;

Fig. 3 is a detection flow chart of the ceramic heating wire industrial and mining detection method provided by the embodiment of the present invention.

Detailed ways

In order to make the content, purpose and technical solution of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the technical solution of the embodiment of the present invention is: a ceramic heating wire working condition detection circuit, including: control module ①, electronic switch module ②, heating wire driving module ③, heating wire protection module ④, detection processing Module ⑤, voltage conversion module ⑥. An electronic switch module ②, the input end of the electronic switch module ② is connected to the control pulse signal output end of the control module ①, and the output end of the electronic switch module is connected to the signal input end of the heating wire drive module ③; The heating wire driving module ③, the power input end of the heating wire driving module ③ is connected to the positive power supply of the detection circuit, and the circuit power output end of the heating wire driving module ③ is connected to the heating wire protection module ④; the heating wire The protection module ④, the input end of the heating wire protection module ④ is connected to the feedback signal input end A of the detection processing module ⑤; the detection processing module ⑤, the detection signal input end B of the detection processing module ⑤ is connected to the control The detection signal output end of module ①, the detection signal output end C of the detection processing module ⑤ is connected to the feedback voltage input end of the voltage conversion module ⑥; the voltage conversion module ⑥, the output end of the voltage conversion module ⑥ is connected to The feedback signal input terminal of the control module ①.

Fig. 2 is a schematic circuit diagram of a ceramic heating type industrial and mining detection circuit provided by an embodiment of the present invention, and the specific circuit connection of the industrial and mining detection circuit is as follows.

The circuit of the electronic switch module ② is composed of transistor Q ₁ , capacitor C ₄ , resistors R ₅ and R ₆ ; the resistor R ₅ is connected to the control signal output terminal of the control module ① and the base of transistor Q ₁ to realize the limit of the base of transistor Q ₁ The role of current flow; capacitor _C4 is connected between the base of transistor _Q1 and resistor _R5 ; resistor _R6 is connected between the positive pole of the detection circuit power supply and the collector of transistor _Q1 to realize current limiting protection for the collector effect.

The heating wire drive module ③ circuit includes: automatic protection power MOSFET power driver Q ₂ , resistor R ₇ , diode D ₂ and capacitor C ₁ ; the resistor R ₇ is connected to the signal output terminal of the electronic switch module ② circuit and the power MOSFET power driver Q ₂ Between the grids of the gates, the signal integrity problems such as signal overshoot can be weakened or eliminated; the capacitor C ₁ is connected between the drain of the power MOSFET power driver Q ₂ and the power ground plane of the detection circuit; the drain of the power MOSFET power driver Q ₂ The pole is connected to the positive pole of the power supply of the detection circuit, and the source of the power MOSFET power driver _Q2 is connected to the P pole of the diode D2; the detection circuit utilizes the unidirectional conduction characteristic of the diode _D2 to prevent the detection current from flowing backward into _the The source of the power MOSFET power driver _Q2 , thereby protecting the safety of the device.

The heating wire protection module ④ circuit includes: ceramic heating wire R _GP , capacitor C ₃ , fuse F ₁ and transient suppressor D ₁ ; capacitor C ₃ and diode D ₁ are connected between the N pole of diode D ₂ and the detection circuit Between the ground planes of the power supply; the fuse F ₁ is connected between the ceramic heating wire R _GP and the power ground plane of the detection circuit, and plays an over-current protection role for the ceramic heating wire R _GP .

The detection processing module ⑤ circuit includes: resistance R ₁ , resistance R ₂ , resistance R ₃ , resistance R ₄ , capacitance C ₂ and diode D ₃ ; resistance R ₁ is connected to the feedback signal input terminal A and resistance R of the detection processing module circuit ₂ ; the other end of the resistor R ₂ is directly connected to the N pole of the diode D ₃ ; the P pole of the diode D ₃ is connected to the detection signal input terminal B of the detection processing module ⑤; the diode D ₃ is used to prevent the ceramic heating wire from driving The current is poured into the circuit of the control module ①, causing the control module ① to malfunction; the other end of the resistor _R4 is connected to the power ground of the detection circuit.

Voltage conversion module ⑥ circuit includes: analog/digital converter U ₅ ; the input end of analog/digital converter U ₅ is connected at the detection signal output terminal C of detection processing module ⑤, and the output end of analog/digital converter U ₅ is connected To the feedback signal input terminal of the control module ①.

Fig. 3 is a flow chart of the detection method of the working condition of the ceramic heating wire according to the embodiment of the present invention. The detection method of the ceramic heating wire cooperates with the working condition detection circuit to detect various working conditions of the heating wire. The method for detecting the working condition of the ceramic heating wire includes the following steps:

S1: Before starting to detect the state of various working conditions of the ceramic heating wire, first record the current control command of the control module ①;

S2: Determine whether the command of the control module ① is to open the ceramic heating wire;

S3: If yes, then the feedback signal input terminal of the control module ① directly reads the data at the output terminal of the voltage conversion module ⑥;

S4: If not, the detection signal output port of the control module ① sends a detection signal, and the feedback signal input port reads the data at the output end of the voltage conversion module ⑥;

S5: Turn off the heating wire detection signal at the detection signal output end of the control module ① in the ceramic heating wire detection circuit;

S6: According to the voltage data output by the voltage conversion module ⑥ received by the control module ①, directly judge the various working conditions of the ceramic heating wire;

Table 1 The state of the corresponding motor under different detection voltages

Among them: V _CC1 : the detection signal voltage output by the detection signal output terminal of the control module ①;

V _D2 : forward conduction voltage drop of diode D ₂ ;

V _D3 : forward conduction voltage drop of diode D ₃ .

S7: According to the determined working state of the ceramic heating wire, the control module adopts corresponding processing procedures to ensure the normal operation and safety of the system.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. , Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. A ceramic heating wire working condition detection circuit, comprising: an electronic switch module, the input end of the electronic switch module is connected to the control pulse signal output end of the control module, and the output end of the electronic switch module is connected to the The signal input end of the heating wire driving module; the heating wire driving module, the power input end of the heating wire driving module is connected to the positive power supply of the detection circuit, and the power output end of the heating wire driving module circuit is connected to the heating wire A wire protection module; a heating wire protection module, the input end of the heating wire protection module is connected to the feedback signal input end A of the detection processing module; a detection processing module, the detection signal input end B of the detection processing module is connected to the The detection signal output terminal of the control module, the detection signal output terminal C of the detection processing module is connected to the feedback voltage input terminal of the voltage conversion module; the voltage conversion module, the output terminal of the voltage conversion module is connected to the control module The feedback signal input terminal. 2. The ceramic heating wire working condition detection circuit according to claim 1, wherein the electronic switch module circuit is composed of a triode _Q1 , a capacitor _C4 , resistors _R5 and _R6 ; the resistor _R5 is connected to the The control module controls the signal output terminal and the base of the transistor _Q1 to realize the current limiting effect on the base of the transistor _Q1 ; the capacitor _C4 is connected between the base of the transistor _Q1 and the resistor _R5 ; the resistor _R6 It is connected between the positive pole of the power supply of the detection circuit and the collector of the triode _Q1 to realize the current limiting protection of the collector. 3. The ceramic heating wire working condition detection circuit according to claim 1, wherein the heating wire driving module circuit comprises: automatic protection power MOSFET power driver Q ₂ , resistor R ₇ , diode D ₂ and capacitor C ₁ ; Resistor R ₇ is connected between the signal output terminal of the electronic switch module circuit and the gate of the power MOSFET power driver Q ₂ , so as to reduce or eliminate signal integrity problems such as signal overshoot; capacitor C ₁ is connected to the between the drain of the power MOSFET power driver Q ₂ and the power ground plane of the detection circuit; the drain of the power MOSFET power driver Q ₂ is connected to the positive power supply of the detection circuit, and the source of the power MOSFET power driver Q ₂ is connected to the power ground of the detection circuit The P pole of the diode _D2 ; the unidirectional conduction characteristic of the diode _D2 is utilized in the detection circuit to prevent the detection current during detection from pouring back into the source of the power MOSFET power driver _Q2 , thereby protecting the safety of the device. 4. The ceramic heating wire working condition detection circuit according to claim 1, wherein the heating wire protection module circuit comprises: ceramic heating wire R _GP , capacitor C ₃ , fuse F ₁ and transient suppressor D ₁ ; Capacitor C ₃ and diode D ₁ are connected between the N pole of the diode D ₂ and the power ground plane of the detection circuit; the fuse F ₁ is connected between the ceramic heating wire R _GP and the power ground plane of the detection circuit , to protect the ceramic heating wire R _GP from overcurrent. 5. The ceramic heating wire working condition detection circuit according to claim 1, characterized in that, the detection processing module circuit comprises: resistance R ₁ , resistance R ₂ , resistance R ₃ , resistance R ₄ , capacitance C ₂ and Diode D ₃ ; resistor R ₁ is connected between the feedback signal input terminal A of the detection processing module circuit and the resistor R ₂ ; the other end of the resistor R ₂ is directly connected to the N pole of the diode D ₃ ; the diode D The P pole of ₃ is connected to the detection signal input terminal B of the detection processing module; the diode D ₃ is used to prevent the ceramic heating wire drive current from pouring into the control module circuit, causing the control module to fail; the resistor R ₄ The other end is connected to the power supply ground of the detection circuit. 6. ceramic heating wire operating condition detection circuit as claimed in claim 1, is characterized in that, described voltage conversion module circuit comprises: analog/digital converter U ₅ ; The input end of analog/digital converter U ₅ is connected at said At the detection signal output terminal C of the detection processing module, the output terminal of the analog/digital converter _U5 is connected to the feedback signal input terminal of the control module. 7. A method for detecting the working condition of a ceramic heating wire, characterized in that the method for detecting the working condition of the ceramic heating wire cooperates with a circuit for detecting the working condition of the ceramic heating wire to detect various working conditions of the ceramic heating wire. The ceramic heating wire detection method includes the following steps: S1: Before starting to detect the state of various working conditions of the ceramic heating wire, first record the current control command of the control module; S2: Determine whether the command of the control module is to turn on the ceramic heating wire; S3: If yes, the feedback signal input terminal of the control module directly reads the data at the output terminal of the voltage conversion module; S4: If not, the detection signal output port of the control module sends a detection signal, and the feedback signal input port reads the data at the output end of the voltage conversion module; S5: Turn off the heating wire detection signal at the detection signal output end of the control module in the ceramic heating wire detection circuit; S6: According to the voltage data output by the voltage conversion module received by the control module, directly judge the various working conditions of the ceramic heating wire; S7: According to the determined working state of the ceramic heating wire, the control module adopts corresponding processing procedures to ensure the normal operation and safety of the system.

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